Aristopus humeratus Fedorenko, 2021

Fedorenko, D. N., 2021, Notes on the genera Aristopus, Cosmodiscus and Metabacetus (Coleoptera: Carabidae: Pterostichini: Abacetina), with description of three new species from Vietnam, Russian Entomological Journal 30 (4), pp. 413-429 : 421-423

1. Aristopus humeratus Fedorenko , sp.n.

Figs 20 , 29–30, 36, 38–39, 50, 56–57.

MATERIAL. Holotype ♂ ( ZMMU) labelled: ‘S[outh] Vietnam, N[orthern part of] Dongnai Pr [ovince]./ Nam Cat Tien Nat [ional]. Park / Exped [ition of the Joint]. Russ [ian].- Vietnamese / Tropical Centre / at light HQL-450 10./ leg. D.Fedorenko. VI.2005 ’. Paratypes ( SIEE, ZISP) : 3 ♂♂, 7 ♀♀, same data, but various dates, including 2–3. and 10–11. VI.2005 ; 2 ♀♀, Vietnam, Binh Phuoc Prov., Bu Gia Map Natn. Park , 12°11´37´´N / 107°12´21´´E, h= 350– 540 m, at light, 17. or 22–22.IV.2009, leg. D.Fedorenko’ ; 2 ♂♂, ‘ Vietnam, Lam Dong Province, 35 km NNW of Bao Loc, Loc Bao env., h= 650 m, 11°50´12´´N / 107°38´25´´E, at light, 17–22.IV.2012, D.Fedorenko leg. ’; ♀, ‘N-Vietnam, Ninh Binh Prov., 7.5 km SSW of Nho Quan, Dong Tam vill., 20°15´08´´N / 105°44´09´´E, h~ 100 m, at light, 1–5. V.2019, A. Prosvirov leg. ’; ♂, 2 ♀♀, ‘N Thailand, Mae Hong Son Prov., env. Pai , 19°21´42´´N / 98°27´46´´E — 19°22´N / 98°30´29´´E, h~ 600 m, 27.IV–9. V.2013, leg. I.Melnik’ .

Additional material: ♀ ( ZSM), Thailand , Chiang Mai, Doi Intha Non Natn. Park, h= 332 m, 18.50°N 98.67°E, 21.08.2012 ( V. K. Zinchenko) ; ♀ ( ZISP), Nepal, Loc.no.26, Nuwakot , Ranipauwa env., 27°47.24´N, 85°16.17´E, 1730 m, 6.V.2000, Expedition A.Konstantinov, S.Lingafelter & M.Volkovitsh .

DIAGNOSIS. The Oriental species of Aristopus with maculate elytra, distinguishable from the western species A. picturatus ( Andrewes, 1920) , comb.n., by having no elytral parascutellar or discal setae, and humeral maculae being smaller. The presence of the humeral macula differentiates the new species from both A. latus ( Andrewes, 1947) , and A. kaszabi ( Jedlička, 1954) , and very long frontal sulci distinguish it from the latter three. Totally obliterate apical bead of pronotum and unisetose metafemur are additional unique features.

DESCRIPTION. BL 6–8 mm. Body ( Fig. 20 ) shiny black, pronotum dark brown black, slightly reddish along both base and apex; anterior half of clypeus, labrum, explanate lateral margin of pronotum, mouthparts, legs, antennae, elytral epipleura and pattern, as well as abdominal sternite VII in apical half, red or reddish yellow. Elytral pale pattern includes reflexed lateral margin (outside stria 9), apex, humeral spot and two quadrate preapical spots. Humeral spot spanning intervals 6–9 in basal 1/4–1/5; anterior preapical spot on intervals 4 and 5 (sometimes only on 4), posterior one slightly smaller, running on interval 2 and 3, and touching the anterior spot; pale apex shorter than to as long as posterior preapical spot, laterally almost reaching the level of apical margin of anterior preapical spot. Underside reddish brown to brown black.

Microsculpture consisting of extremely fine and very dense transverse lines along pronotal base and on elytra in female, mostly absent or almost so in male; dorsal iridescence accordingly varying between very distinct to imperceptible.

Head with large hemispherical eyes. Frontal sulci very long, deep and divergent anteriorly, less deep and slightly S-shaped at anterior supra-ocular seta, moderately deep behind, reaching and diverging toward posterior supra-ocular seta. Labrum apically subsinuate to truncate. Antennae barely or indistinctly longer in male than in female, almost reaching or surpassing pronotal base by apical half of antennomere 11.

Pronotum subquadrate, transverse, half wider than long, PW/PL 1.49–1.54 (1.52, n=7), more than two thirds wider than head, PW/HW 1.66–1.71 (1.70). Sides rounded, not or minutely sinuate just in front of obtuse and apically blunt basal angles. Explanate lateral margin slightly yet abruptly reflexed, becoming increasingly wide toward base, very wide basally; lateral bead fine and entire. Base a third wider than apex, PB/PA 1.28–1.40 (1.33), truncate medially, slightly oblique and more or less distinctly, sometimes vaguely, beaded outside basal sulci. These deep, parallel, running on basal third, obliterate basally. Apical margin truncate to slightly convex at middle; apical angles projecting, right to very slightly acute, with apices blunt; apical bead totally obliterate. Median line very fine, mostly obliterate basally and apically, to almost imperceptible. Disc otherwise convex and smooth, basal sulci finely and confluently punctate at bottom, sometimes with a few punctures at sides, explanate lateral margin finely and sparsely to vaguely punctate, more densely and more distinctly along lateral and basal beads.

Elytra about a third longer than wide, EL/EW 1.36–1.39 (1.37), and a fourth wider than pronotum, EW/PW 1.26–1.31 (1.27), almost parallel-sided, broadest behind middle, slightly yet distinctly sinuate before apex; apices blunt and almost truncate combined; sides varying between very slightly round- ed and barely concave. Humeri distinct, each in posteromedial view without or with a minute pointed tooth; basal ridges slightly concave combined, humeral angle very obtuse and somewhat rounded. Striae entire, deep, sulcate, impunctate, crenulate or not, much deeper toward apex, with inner two often shallower on disc. Intervals flat to subconvex, convex or very so in apical 1/3–1/4. Neither parascutellar nor discal setae present. Stria 7 with two apical setae. USS (see ‘Comments’ below) with US 10 large, adjoining stria 8 and slightly separated from stria 9.

Underside: Prosternum without median groove, prosternal process not apically beaded. Mesepisterna in anterior half, metepisterna, abdomen except along middle, finely and densely punctate; sometimes propleura close to anterior margin of procoxae and extreme sides of metaventrite with a few similar punctures. Abdominal sternite VII bisetose in male, quadrisetose in female.

Legs. Protibia apically dilated, with three latero-apical spines. Mesotibia with 4–5 spiniform anterolateral setae, inner setal brush consisting of 8+1 or 9+1 setae; metatibia with 2–4 spiniform setae at outer margin. Metafemur with the only anterolateral seta, distal. Basal three protarsomeres dilated and biserially squamose in male or toothed at latero-apical angles in female, teeth being very small on protarsomere 3.

Aedeagus ( Figs 38–39 , 50, 56–57 ): Internal sac with three sclerotized folds in apical half.

Abdominal urites VIII and IX in female as in Figs 29–30, 36.

NAME. Refers to the elytral humeral macula as a characteristic feature of this species.

GEOGRAPHIC DISTRIBUTION. Nepal, Thailand, Vietnam, and probably also Laos. In Vietnam, the species is more frequent in the south than in the north.

HABITATS AND HABITS. Virtually all the specimens examined have been taken at light at the edges of broad-leaved monsoon forests.

COMMENTS. The new species is very similar to A. latus from Myanmar and A. kaszabi from Taiwan, each described based on a single female specimen within either Cosmodiscus or Caelostomus Macleay, 1825 (as Drimostoma Dejean, 1831 ), respectively. Those two are distinctive in only having short frontal sulci, the elytra without pale humeral spot, and the pronotal apical bead interrupted medially. This high similarity between the three taxa makes subspecies status of A. humeratus sp.n. not improbable, which problem is hardly soluble until more material, including males of A. latus and A. kaszabi , is examined.

USS patterns vary in the new species, since intermediate seta US 7 ranges considerably in its position. In particular, patterns 6–1–7, 6–1–7 or 7–7, and 6–1–8 or 7–8 have been found in three, 14, and three specimens examined, respectively .

Figures

Figs 19–24. Dorsal habitus: 19 — Aristopus picturatus, ♀ from Anuradhapura env., Sri Lanka; 20 — A. humeratus sp.n., paratype ♂ from env. Pai, Thailand; 21 — Cosmodiscus platynotus, ♀ from the Bi Doup — Nui Ba Nature Reserve; 22 — C. rufoapicalis sp.n., holotype; 23 — C. rufolimbatus, holotype; 24 — C. louwerensi, paratype. Рис. 19–24. Габитус дорЗально: 19 — Aristopus picturatus, ♀ иЗ окр. Анурадхапура, Шри Ланка; 20 — A. humeratus sp.n., паратип ♂ иЗ окр. Паи, Таиланд; 21 — Cosmodiscus platynotus, ♀ иЗ Запов. Бидуп-Нуйба; 22 — C. rufoapicalis sp.n., голотип; 23 — C. rufolimbatus, голотип; 24 — C. louwerensi, паратип.

Figs 38–49. Median lobe of aedeagus: 38–39 — Aristopus humeratus sp.n., paratype ♂ from env. Pai, Thailand; 40–41 — A. picturatus, ♂ from Vilpattu, Sri Lanka; 42–43 — Cosmodiscus platynotus; 44–45 — C. rufoapicalis sp.n., holotype; 46–47 — C. louwerensi, paratype; 48–49 — C. mirei; 38, 40, 42, 44, 46, 48 — left aspect; 39, 41, 43, 45, 47, 49 — right aspect; vc — ventral longitudinal carina. Scale bars: 1 mm. Рис. 38–49. СреднЯЯ долЯ Эдеагуса: 38–39 — Aristopus humeratus sp.n., паратип ♂ иЗ окр. Паи, Таиланд; 40–41 — A. picturatus, ♂ иЗ Вильпатту, Шри Ланка; 42–43 — Cosmodiscus platynotus; 44–45 — C. rufoapicalis sp.n., голотип; 46–47 — C. louwerensi, паратип; 48–49 — C. mirei; 38, 40, 42, 44, 46, 48 — слева; 39, 41, 43, 45, 47, 49 — справа; vc — продольный вентральный киль. Масштаб: 1 мм.

Figs 50–67. Aedeagus: 50, 56–57 — Aristopus humeratus sp.n., paratype ♂ from env. Pai, Thailand; 51, 58–59 — A. picturatus, ♂ from Vilpattu, Sri Lanka; 52, 60–61 — Cosmodiscus platynotus; 53, 64–65 — C. rufoapicalis sp.n., holotype; 54, 62–63 — C. louwerensi, paratype; 55, 66–67 — C. mirei; 50–55 — median lobe, ventral aspect; 56, 58, 60, 62, 64, 66 — right paramere, left aspect; 57, 59, 61, 63, 65, 67 — left paramere, right aspect. Scale bar: 1 mm. Рис. 50–67. Эдеагус: 50, 56–57 — Aristopus humeratus sp.n., паратип ♂ иЗ окр. Паи, Таиланд; 51, 58–59 — A. picturatus, ♂ иЗ Вильпатту, Шри Ланка; 52, 60–61 — Cosmodiscus platynotus; 53, 64–65 — C. rufoapicalis sp.n., голотип; 54, 62–63 — C. louwerensi, паратип; 55, 66–67 — C. mirei; 50–55 — среднЯЯ долЯ вентрально; 56, 58, 60, 62, 64, 66 — праваЯ парамера слева; 57, 59, 61, 63, 65, 67 — леваЯ парамера справа. Масштаб: 1 мм.